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Abstract

The objective of this study was to investigate urinary nitrogen (N) excretion, grazing and urination behaviour of dairy heifers
grazing pasture, chicory and plantain. A 35-day trial was conducted with 56 Friesian x Jersey heifers aged 9-10 months. Heifers
were blocked into five treatments balanced for their live weight and breeding worth: 100% ryegrass/white-clover pasture (PA; n
= 12); 100% chicory (CH; n = 10); 100% plantain (PL; n = 12); 50% pasture + 50% chicory (PA+CH; n = 10); and 50% pasture
+ 50% plantain (PA+PL; n = 12). Feed was offered every three days with allowance calculated according to feed requirement for
maintenance plus live weight gain of 0.8 kg/day. Measured urinary-N concentration, estimated daily urinary-N excretion (UN) and
urinary output were similar among treatments. During the first six hours after feed allocation, heifers spent more time idling and
less time ruminating on CH and PL than on PA. The CH and PA+CH groups urinated more frequently than other groups. Data from
this study indicate that heifers grazed chicory urinated more frequently without increasing daily UN and may potentially reduce N
loading from soil. Future study is needed to take account of urinary N excretion diurnal variation.

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For over seventy years the New Zealand Society of Animal Production has played an important role as a forum fostering research in all areas of animal production including production systems, nutrition, meat science, animal welfare, wool science, animal breeding and genetics.